Hassan Ali Haidar, who was dismantling the “strange device”, was killed after a jet detonated it remotely while flying above the coastal town of Adloun, 17 kilometers (11 miles) south of Sidon, on Friday.
The Lebanese army confirmed the incident, saying Israel detonated the device “from a distance” through the aircraft.
The device had reportedly been planted on some telecommunications network.
Similar surveillance devices have previously been planted by Tel Aviv in southern Lebanon, a move condemned by Lebanese and officials of the United Nations.
The Tel Aviv regime has declined to comment on the incident.
The Israeli regime launched a war of aggression on Hezbollah in 2006. The conflict killed about 1,200 Lebanese people and 160 Israelis.